There has been developed an instrument that operates by using electric power generated by energy harvesting for harvesting minute energy from a surrounding environment such as light, heat, and oscillation.
For example, Japanese Patent Publication No. 4824277 (Patent Literature 1) discloses the following technique.
That is, a sensor system includes: at least one voltage generator that converts nonelectric energy into electric energy; at least one energy storage unit connected to a back position of the voltage generator; at least one voltage converter connected to the energy storage unit so that an output signal of the self matches the operation performed by a processor control unit; at least one sensor; and at least one transmission unit that performs wireless transmission of a transmission telegram which is generated by the processor control unit and which includes at least one measured value of the at least one sensor.
In the sensor system, there is provided a semiconductor timer circuit configured by the ULP technique for realizing a long-hour active cycle in the case where the energy supply is imperfect.
The timer circuit is triggered when the voltage of the at least one energy storage unit reaches a predetermined level. After a predetermined time since the time point when the timer circuit is triggered, the timer circuit starts the processor control unit and the transmission unit so as to transmit at least one transmission telegram.
The at least one voltage generator is configured in a size that does not allow the voltage generator to generate sustainably-operating electric power when an attempt is made to directly drive the processor control unit. The transmission telegram further includes one identification code.